To drain or not to drain pool with high CYA?

[stevemac213]

Hi there. New to this forum and have a question...I drained my pool a few months back because of high CYA but apparently didn't take enough water out since it is too high once again, (about 200).

My question is...should I drain it now and keep it up over the winter, or just let it go green and drain it come springtime, and start over?

Any and all responses are greatly appreciated...thanks.
Steve

[PoolDoc]

What size pool? What type? (Concrete, vinyl)

You probably do NOT want to let it go green -- the high CYA will probably be biodegraded to ammonia. It may subsequently be converted to nitrates or nitrogen gas, but if it stays as ammonia, you will have a horrendous spring start-up problem.

[stevemac213]

Thanks Ben. I filled in all my pool info but it is not showing up for some reason?

It is a concrete 27K gal in-ground pool.

It is already turning green since I've ignored it for the past week, (since pool season is over). Do you think I should drain it now rather than wait? I was told to wait because the CYA may go down over the winter and therefore I would not have to drain as much? If I did drain it now, how much should I take out...all of it or no?

Thanks!

[PoolDoc]

Read the Best Guess page, linked in my blue signature block -- you *can* operate the pool with high CYA.

If you're going to let the pool go green, I'd wait till spring to drain and refill. The reason is, if you end up with ammonia in the water in spring, you'll probably want to drain 100% -- but there's no way we've found to determine exactly what the bacteria will do in YOUR pool, so right now it's just a crap-shoot whether you end up with CYA => nitrogen gas OR CYA => nitrates OR CYA => ammonia.

If you don't want to risk it (and algae stains, etc) by abandoning the pool for 6 months, you need to clean things up NOW -- use plain household bleach in 10 gallon doses till you read an OTO 'orange' level. AND . . . order a K2006 kit so we can get accurate test results, and work out a 'next' step.

[stevemac213]

Ok, draining it now but I only have a small pump so may take a couple days. Is there anything I should be doing while it's draining? (i.e.. sweeping sides/bottom, etc)

Thanks Ben.

[PoolDoc]

Yeah, what you said.

You don't want stains or algae to dry on the sides. Using a hose with a nozzle is probably the easiest solution.

[stevemac213]

Ok...makes sense.

How much do you think I should drain? (50%....75%....100%)?

Thanks.

[PoolDoc]

Either drain it all, OR purchase a K2006 kit, and let us walk you through a high-range CYA test to see what your actual levels are. CYA test results from strips are too unreliable to depend on.

[stevemac213]

Actually, I do have a K - 2006 test kit...that's where I got the high CYA reading from. It was past 100 when I tested it with straight pool water so I did 50/50 pool water/tap water and that's how I got the reading which was closer to 200.

Any help you can provide is much appreciated.

Thanks.

[PoolDoc]

If the 200 ppm is valid, you probably want to drain 3/4 (to 50 ppm) if you are going to use bleach next year. If you are going to use trichlor (which adds CYA) you may want to drain more.